The long range objective of this project is to utilize catecholamine-producing cell lines for the therapy of Parkinson's disease (PD). The specific aims of this project are to develop the strategies and techniques for utilizing somatic cell replacement therapy with 1-dopa or catecholamine-secreting cell lines in animal models of PD, including the MPTP model. During the current project period, we intend to identify existing catecholamine-secreting cell lines and produce others and evaluate their use as intracerebral transplants into recipient animals. The parameters of importance which we will monitor include the growth, survival and viability of the cells after implantation into the basal ganglia and the host response in terms of acceptance or rejection of the implant. We will evaluate the role of the immune system in acceptance or rejection. We will also evaluate the possibility that grafting induces regrowth of damaged dopaminergic neurons in the host. We will also evaluate the behavioral effects of these implanted cells in restoring dopaminergic function in lesioned animals. The methods of assessment of survival are anatomical, using histochemical localization and biochemical and behavioral. We will produce catecholamine-secreting cell lines for implantation by either immortalizing mesencephalic neurons which already express tyrosine hydroxylase and dopamine-beta- hydroxylase by the insertion of oncogenes or by inserting the cDNA for tyrosine hydroxylase into 3T3 or other immortal somatic cells. After monitoring these cell lines for expression of 1-dopa, we will utilize these genetically-engineered cells in the transplant model and evaluate their survival. The final series of experiments will utilize the knowledge obtained earlier to employ primary rat fibroblasts as the recipient tissue for the TH gene. These fibroblasts will be selected for secretion of 1-dopa and will then be used as implants into either nude athymic mice or syngeneic rats. The survival, biochemistry and behavioral effects of these implants will be evaluated.